The present application relates to lateral power semiconductor devices, and more particularly to lateral power semiconductor devices which incorporate fixed or permanent electrostatic net charge.
Note that the points discussed below may reflect the hindsight gained from the disclosed inventions, and are not necessarily admitted to be prior art.
Power MOSFETs are widely used as switching devices in many electronic applications. In order to minimize the conduction power loss it is desirable that power MOSFETs have a low specific on-resistance (RSP or R*A), which is defined as the product of the on-resistance of the MOSFET multiplied by the active die area. In general, the on-resistance of a power MOSFET is dominated by the channel resistance and the drift region resistances which include the channel resistance, spreading resistance and the epitaxial layer resistance.
In the parent applications referenced above, and in many other commonly owned applications, the present inventors have proposed a variety of new vertical and lateral structures which improve on-resistance and/or breakdown characteristics by incorporating fixed or permanent charges. FIGS. 1(a)-1(c), 2(a), and 2(b) show lateral device structures disclosed in the various parent applications, but it is important to note that those structures are not prior art against the present application, since priority has been claimed back to their disclosures.